NEW YORK (CBSNewYork) — He’s a high school dropout who started the social networking site Tumblr six years ago. On Monday, New Yorker David Karp officially sold the site to Yahoo! for more than $1 billion.

If you’re a social media junkie, you and a few million others know what Tumblr is. If not, you might be wondering why Yahoo! would pay a king’s ransom for it.

Tumblr us a social networking website, a cross between Twitter and Facebook, and, as of Monday, is owned and operated by Yahoo!.

“Yahoo! acquired one of New York’s most successful start-ups, Tumblr, to become part of the Yahoo! Portfolio,” Yahoo! President and CEO Marissa Mayer said.

Karp is now an extremely wealthy 26-year-old. He has been featured on the cover of Forbes’ 30 under 30. He reportedly lives with his girlfriend in an unassuming apartment in Williamsburg, Brooklyn. CBS 2’s Emily Smith also found out he went to the prestigious Bronx High School of Science for one year before dropping out at the age of 15 and started homeschooling but never earned his diploma.

Paul Levinson is a professor of media studies at Fordham University.

“No one knows much about him at all. It’s interesting he was home schooled. You have Bill Gates a college dropout and really the same as Steve Jobs,” Levinson said.

Levinson said by selling Tumblr to Yahoo! Karp is about $275 million richer. The rest of the billion dollar transaction will be paid to investors.

Whether the marriage between Tumblr and Yahoo! will help turn-around Yahoo! remains to be seen.

And while Karp will hold his reign as CEO, his life is forever changed.

“A lot of people are concerned he sold out. I don’t think so. Let him make money from it,” Levinson said.

Karp founded Tumblr on Manhattan’s Upper West Side in his mother’s small apartment in 2007.

Tumblr’s headquarters will remain in New York City. The site sees 900 posts a second.